1. Field of the Invention
The present invention relates to a position detecting system and a position detecting method, and particularly, to a position detecting system and a position detecting method, which detect the position of a capsule body-insertable apparatus to be introduced into a subject by using a magnetic field.
2. Description of the Related Art
In recent years, there has been developed a capsule detected object (hereinafter, referred to as a capsule endoscope) provided with an imaging element (for example, refer to Japanese Laid-open Patent Publication No. 2006-271520). The capsule endoscope, for example, is introduced into a subject via the oral route to capture an image of the interior of the subject, and transmits the acquired image (hereinafter, referred to as the in-vivo image) to an external device disposed out of the subject in a wireless manner. An operator visually recognizes the in-vivo image received in the external device, thereby diagnosing the condition and the like of the subject.
In a medical system using the capsule endoscope as described above, it is desired to accurately recognize the position, direction and the like of the capsule endoscope in order to specify a place to be imaged and guide the position of the capsule endoscope in the subject, for example. In this regards, Japanese Laid-open Patent Publication No. 2006-271520 has disclosed a position detecting system in which a resonant circuit (hereinafter, referred to as an LC resonant circuit) including a coil (L) and a capacitor (C) is provided in a capsule endoscope to detect a resonant magnetic field, which is generated by an alternating magnetic field (hereinafter, referred to as a driving magnetic field) applied from an exterior of the LC resonant circuit, using a detecting coil provided in the external device, thereby detecting the position and direction of the capsule endoscope.